Elevator cages usually have a brake device which is designed as a safety brake device for cases of emergency. This safety brake device is triggered by a speed limiter and stops the elevator cage by means of wedge braking at the guide rails if a nominal speed is exceeded. In normal operation, on the other hand, use is made of a brake device which is coupled with a drive and, for example, ensures that the elevator cage is stopped precisely at the level of the respective story door.
The drive of the elevator cage is in turn usually carried out by means of a drive pulley around which the supporting and drive means are guided. The brake device for normal operation is coupled with the drive and when required brakes the drive pulley so that the elevator cage—for example at a story stop—is held by the braking device.
Precise stopping of the elevator cage at the level of the respective story is not always guaranteed with elevator installations having substantial conveying heights, since the supporting and drive means are subject to stretching, in which case this stretching has to be corrected for stopping of the elevator cage flush with a story.
An elevator installation with an elevator cage with two vertical lateral guide structures and with two counterweights movable along the guide structures and with an own drive has become known from PCT/EP2009/059077. The elevator cage is connected by support means with the counterweights. Flat drives serve as independent drives. The flat drives are attached to mutually opposite cage sides of the elevator cage, wherein each flat drive has a rim gear engaging in complementary toothings provided at the guide structures. A rotational movement of the rim gear is thus converted into a vertical movement of the elevator cage. The rim gear is connected with the brake disc on which a disc brake acts.